Examples of our findings include: 1) We evaluated in healthy subjects a promising radioligand to quantify the cannabinoid CB1 ("marijuana") receptor in brain. Postmortem studies suggest that the CB1 receptor is decreased in the brains of patients with schizophrenia. In the coming year, we will use our new radioligand to study the CB1 receptor in the living brains of patients withjschizophrenia. 2) We studied in healthy subjects a promising probe to measure inflammation and have positive preliminary results in patients with Alzheimers disease. We will expand these studies to understand the extent of inflammation in brains of patients with Alzheimer's disease and its involvement in the course of illness. We also plan to study patients with autism, for whom inflammation in brain may also play an important role. 3) We studied a cAMP enzyme involved in intracellular signaling that may be involved with depression. We completed studies in healthy subjects and are now studying whether this marker is abnormal in patients with depression, before and during antidepressant treatment. 4) We recently completed a study in patients with panic disorder of a probe for the NK1 receptor. This novel receptor is a target for medication treatment in anxiety disorders. And we found reduction of this receptor in brains of patients with panic disorder.